The present invention relates to a penpoint assembly and a writing instrument employing the same, and particularly relates to a penpoint assembly comprising a penpoint made of a metal plate cut off at both the side edges thereof as a taper toward the writing tip of the penpoint and having a slit along the center line of the penpoint, an ink guide core through which ink from an ink storage means is guided to the slit, and a support member for supporting the ink guide core, and to a writing instrument employing the penpoint assembly and constituted so that the ink is guided to the writing tip of the penpoint through an ink flow regulating portion.
A conventional penpoint assembly comprising a penpoint made of a metal plate having a slit along the center line of the penpoint, a support member and an ink guide core interposed between the penpoint and the support member, and a conventional writing instrument employing the penpoint assembly were disclosed in the European Patent Application (OPI) No. 209,342A (the term "OPI" as used herein means an "unexamined published application"). The slit of the metal plate constituting the penpoint extends along the axial direction of the penpoint assembly similarly to a fountain pen. Ink in the ink guide core extending in tight contact with the penpoint under the slit in the axial direction of the penpoint assembly is introduced into the slit so that the ink flows out from the writing tip of the penpoint. We studied the ink discharge mechanism constituted by the penpoint and the ink guide core in combination, the machinability or workability of the penpoint and so forth. As a result, we obtained some knowledge about them and found a number of problems in them, as mentioned from now on. It is substantially inevitable to perform shearing to make the slit in the metal plate, especially when the metal plate is a thin stainless steel plate. As for the shearing, the mutual non-coincidence of the sheared portions of the metal plate at the writing tip of the penpoint increases in proportion to the length of the slit. The increase in the length of the slit does not contribute to improving the outflow of the ink. The outflow of the ink depends on only a few millimeters of the length of the slit from the writing tip of the penpoint. It is essential to make the surface of the tip of the ink guide core slightly oversaturated with the ink and connect the ink in the surface of the tip of the core to that in the slit of the penpoint. In the writing instrument employing the penpoint assembly, the rear end of the ink guide core is coupled to an ink suction container housed in the rear portion of a penholder. The ink in the ink suction container cannot be all used for writing, and it is inevitable that 20 to 40% of the ink is left unused in the ink suction container. Since an ink guide core support and a penpoint support are separately formed and the penpoint and the ink guide core are fitted between the ink guide core support and the penpoint support, it is troublesome to assemble them and it is difficult to accurately position them to each other.